1. Field of the Invention
The present invention relates to a system for controlling a route bus service by first collecting information at passage points of buses running on a regular route according to a basic schedule, then estimating the time of arrival of each running bus at a terminal, subsequently modifying the basic schedule so as to enable the route buses to depart from the terminal sequentially at equal time intervals, and displaying service information such as a timetable and so forth on a service indicator installed in each bus.
2. Description of the Prior Art
In the current urban traffic where automobiles occupy a major position, there exist some serious urban problems including traffic congestion and so forth that result from overpopulated city structure, and it is of great importance to secure, in the highly dense urban road network, smooth service of transportation means such as route buses which are operated principally for the public.
Similarly in medium- and long-distance transportation means which serve for communication between cities, there may occur troubles that normal service conforming to basic schedules fails to be achieved due to road construction or traffic accidents on regular routes.
In view of such circumstances mentioned above, one prior invention titled "Method for control of specific automobile service" is known as disclosed in Japanese Patent Publication No. 54-11878 (published on May 18, 1979).
FIGS. 1 through 3 illustrate a conventional apparatus designed for controlling the service of specific vehicles such as route buses. In FIG. 1, a central service controller 1 and ground receivers 2 . . . are connected to each other by means of circuit lines 3 . . . . The ground receivers 2a, 2b, 2c are equipped with antennas 4a, 4b, 4c respectively and are installed at fixed intervals along a road 9 which is a route where buses 5 . . . run according to a basic schedule. In this example the route buses 5a, 5b, 5c are running sequentially in the order of service, and mobile radio units 7a, 7b, 7c equipped with antennas 6a, 6b, 6c are installed in the buses 5a, 5b, 5c respectively together with service indicators 8a, 8b, 8c.
In the system having the above-mentioned constitution for controlling the operation of vehicles such as route buses, each of the service indicators 8 has such a display panel 10 as shown in FIG. 2. On the obverse side of the display panel 10, individual indication contents are exhibited with, for example, a departure indicator lamp 11 showing characters for "departure" and a standby indicator lamp 12 showing characters for "standby". Each of such indicator lamps 11, 12 internally has a blink means such as a light emitting diode. The display panel 10 is attached at an easy-to-see position for a driver in the route bus. Meanwhile, the driver ought to carry with him a service timetable 13 of FIG. 3 when leaving an office or the like to begin the daily route work. There are prepared several kinds of such timetables 13 which are different from one another depending on a schedule number column 14 and a day-of-week column 15 even for the same route. In the contents described on the timetable 13, a terminal name and stop names are shown in the uppermost row 16 . . . , and the times of passage at such bus stops are written respectively in the lower rows 17. The illustrated service timetable 13 represents an exemplary schedule No. 11 for Saturday. This timetable 13 prescribes that the bus departing from the office at 12:11 reaches a first stop "Tarumi" at 12:19, then leaves there at 12:21 after a two-minute rest to pass via a stop "Sannomiya" and reaches a turn point "Okamoto" at 12:51, subsequently leaves there at 12:56 after a five-minute rest and, via "Sannomiya" at 13:08, reaches "Tarumi" at 13:24. Ten minutes later, the bus departs from "Tarumi" again at 13:34 and thereafter the service is kept according to the timetable.
The drivers on their duties with the above timetables 13 run the route buses 5a, 5b, 5c respectively according to the prescribed schedules with adjustment of the departure and arrival times of the buses in conformity to the instructions received from the service controlling system shown in FIG. 1.
Now the operation of the above service controlling system will be described below with reference to FIG. 1. First the radio waves transmitted from the running buses 5a-5c are caught by the antenna 4a-4c of the ground receivers 2a-2c installed at predetermined points on the road 9 of a service route. The waves from the buses 5a-5c are transmitted by the mobile radio units 7a-7c through the antennas 6a-6c at fixed frequencies selected with respect to the individual buses. Therefore the intervals between the route buses 5 running in the order of 5a, 5b, 5c are caught in the form of radio waves by the ground receivers 2a-2c, whose outputs are transmitted via the circuit lines 3 . . . to the central service controller 1. Then the controller 1 estimates the time required for the specific route bus to pass through the sections where the ground receivers 2a-2c are installed. Such estimation is executed by various computations based on the past data in such a manner that, for example, the time to be required for the bus 5c to pass through the section 9a between the ground receivers 2a and 2b is computed by averaging the actually required passage times of the preceding buses 5a, 5b through the section 9a. In another example, the time to be required for the route bus 5b to pass through the section 9b is estimated on the basis of the time actually required for the preceding route bus 5a to pass through the section 9b. In accordance with such estimations, service instructions are outputted from the central service controller 1 to the individual route buses 5a-5c. The instructions are exhibited by turning on the corresponding indicator lamps 11, 12 . . . in the display panels 10 of the service indicators 8a-8c. For example, when the route buses 5b, 5c pass through the ground receivers 2b, 2a, the instructions from the central service controller 1 are transmitted to the service indicators 8b, 8c via the ground receivers 2b, 2a through the antennas 6b, 6c and the mobile radio units 7b, 7c in the route buses 5b, 5c.
Although not shown in FIG. 1, service information indicators for giving certain service instructions to the bus drivers are installed at selected positions along the road 9 in the route sections 9a, 9b, so that the information corresponding to the service instructions to the individual route buses running in such sections are visually presented by the indicators.
Therefore, although each of the route bus drivers carries with him the timetable of FIG. 3, he receives the service instructions so modified as to maintain proper running of each route bus 5 at a fixed interval depending on the degree of traffic congestion in the sections 9a, 9b and so forth of the road 9, whereby the route bus service is controlled properly according to such instructions.
In the conventional route bus service controlling system constituted as mentioned above, if the service information indicators for drivers are installed on the ground, the information required for adjustment of running intervals and so forth are presented by indication lamps. Accordingly, in case confirmation of the information is needed during the running, it becomes necessary to install considerably large indicators for easy notice by the drivers, hence raising a problem that such indicators are not distinguishable with facility from other signboards or the like and are therefore prone to be overlooked.
Furthermore, with respect to the service indicator installed in each bus, merely some items for instruction are indicated (such as instruction "departure" in FIG. 2). It is essentially necessary that all the required information relative to time and so forth be indicated for any bus driver who performs his duty according to the basic schedule. However, due to the absence of a service instruction by such time information, there exist some difficulties in maintaining the scheduled regular time.
The conventional timetable of a service schedule illustrated in FIG. 3 is made of paper and is handed to a driver at his departure from the office. Since it gives merely fixed time information, if the schedule is disordered by traffic conditions, the driver is not permitted to change the schedule by himself and therefore needs to resume the prescribed service time on the basic schedule by shortening the passenger deal time and adjusting the bus speed while keeping the run on the route, or the predetermined schedule is never restored. As the individual drivers do not adjust the time among themselves (each driver makes no time adjustment by himself and tries to secure the proper service conforming to his fixed timetable), once the schedule is rendered out of order, there occurs successive departure of the buses from the terminal and therefore it becomes necessary to modify the schedule in accordance with the traffic conditions. Thus the proper service conforming to the basic schedule is not attainable, resulting in inconvenience for passengers. This is one of the reasons for reduction of the bus utilization rate.